1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/base/src/nsTextFragment.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,239 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +/*
1.9 + * A class which represents a fragment of text (eg inside a text
1.10 + * node); if only codepoints below 256 are used, the text is stored as
1.11 + * a char*; otherwise the text is stored as a char16_t*
1.12 + */
1.13 +
1.14 +#ifndef nsTextFragment_h___
1.15 +#define nsTextFragment_h___
1.16 +
1.17 +#include "mozilla/Attributes.h"
1.18 +#include "mozilla/MemoryReporting.h"
1.19 +
1.20 +#include "nsString.h"
1.21 +#include "nsReadableUtils.h"
1.22 +#include "nsISupportsImpl.h"
1.23 +
1.24 +class nsString;
1.25 +class nsCString;
1.26 +
1.27 +// XXX should this normalize the code to keep a \u0000 at the end?
1.28 +
1.29 +// XXX nsTextFragmentPool?
1.30 +
1.31 +/**
1.32 + * A fragment of text. If mIs2b is 1 then the m2b pointer is valid
1.33 + * otherwise the m1b pointer is valid. If m1b is used then each byte
1.34 + * of data represents a single ucs2 character with the high byte being
1.35 + * zero.
1.36 + *
1.37 + * This class does not have a virtual destructor therefore it is not
1.38 + * meant to be subclassed.
1.39 + */
1.40 +class nsTextFragment MOZ_FINAL {
1.41 +public:
1.42 + static nsresult Init();
1.43 + static void Shutdown();
1.44 +
1.45 + /**
1.46 + * Default constructor. Initialize the fragment to be empty.
1.47 + */
1.48 + nsTextFragment()
1.49 + : m1b(nullptr), mAllBits(0)
1.50 + {
1.51 + MOZ_COUNT_CTOR(nsTextFragment);
1.52 + NS_ASSERTION(sizeof(FragmentBits) == 4, "Bad field packing!");
1.53 + }
1.54 +
1.55 + ~nsTextFragment();
1.56 +
1.57 + /**
1.58 + * Change the contents of this fragment to be a copy of the
1.59 + * the argument fragment, or to "" if unable to allocate enough memory.
1.60 + */
1.61 + nsTextFragment& operator=(const nsTextFragment& aOther);
1.62 +
1.63 + /**
1.64 + * Return true if this fragment is represented by char16_t data
1.65 + */
1.66 + bool Is2b() const
1.67 + {
1.68 + return mState.mIs2b;
1.69 + }
1.70 +
1.71 + /**
1.72 + * Return true if this fragment contains Bidi text
1.73 + * For performance reasons this flag is only set if explicitely requested (by
1.74 + * setting the aUpdateBidi argument on SetTo or Append to true).
1.75 + */
1.76 + bool IsBidi() const
1.77 + {
1.78 + return mState.mIsBidi;
1.79 + }
1.80 +
1.81 + /**
1.82 + * Get a pointer to constant char16_t data.
1.83 + */
1.84 + const char16_t *Get2b() const
1.85 + {
1.86 + NS_ASSERTION(Is2b(), "not 2b text");
1.87 + return m2b;
1.88 + }
1.89 +
1.90 + /**
1.91 + * Get a pointer to constant char data.
1.92 + */
1.93 + const char *Get1b() const
1.94 + {
1.95 + NS_ASSERTION(!Is2b(), "not 1b text");
1.96 + return (const char *)m1b;
1.97 + }
1.98 +
1.99 + /**
1.100 + * Get the length of the fragment. The length is the number of logical
1.101 + * characters, not the number of bytes to store the characters.
1.102 + */
1.103 + uint32_t GetLength() const
1.104 + {
1.105 + return mState.mLength;
1.106 + }
1.107 +
1.108 + bool CanGrowBy(size_t n) const
1.109 + {
1.110 + return n < (1 << 29) && mState.mLength + n < (1 << 29);
1.111 + }
1.112 +
1.113 + /**
1.114 + * Change the contents of this fragment to be a copy of the given
1.115 + * buffer. If aUpdateBidi is true, contents of the fragment will be scanned,
1.116 + * and mState.mIsBidi will be turned on if it includes any Bidi characters.
1.117 + */
1.118 + bool SetTo(const char16_t* aBuffer, int32_t aLength, bool aUpdateBidi);
1.119 +
1.120 + /**
1.121 + * Append aData to the end of this fragment. If aUpdateBidi is true, contents
1.122 + * of the fragment will be scanned, and mState.mIsBidi will be turned on if
1.123 + * it includes any Bidi characters.
1.124 + */
1.125 + bool Append(const char16_t* aBuffer, uint32_t aLength, bool aUpdateBidi);
1.126 +
1.127 + /**
1.128 + * Append the contents of this string fragment to aString
1.129 + */
1.130 + void AppendTo(nsAString& aString) const {
1.131 + if (!AppendTo(aString, mozilla::fallible_t())) {
1.132 + NS_ABORT_OOM(GetLength());
1.133 + }
1.134 + }
1.135 +
1.136 + /**
1.137 + * Append the contents of this string fragment to aString
1.138 + * @return false if an out of memory condition is detected, true otherwise
1.139 + */
1.140 + bool AppendTo(nsAString& aString,
1.141 + const mozilla::fallible_t&) const NS_WARN_UNUSED_RESULT {
1.142 + if (mState.mIs2b) {
1.143 + bool ok = aString.Append(m2b, mState.mLength, mozilla::fallible_t());
1.144 + if (!ok) {
1.145 + return false;
1.146 + }
1.147 +
1.148 + return true;
1.149 + } else {
1.150 + return AppendASCIItoUTF16(Substring(m1b, mState.mLength), aString,
1.151 + mozilla::fallible_t());
1.152 + }
1.153 + }
1.154 +
1.155 + /**
1.156 + * Append a substring of the contents of this string fragment to aString.
1.157 + * @param aOffset where to start the substring in this text fragment
1.158 + * @param aLength the length of the substring
1.159 + */
1.160 + void AppendTo(nsAString& aString, int32_t aOffset, int32_t aLength) const {
1.161 + if (!AppendTo(aString, aOffset, aLength, mozilla::fallible_t())) {
1.162 + NS_ABORT_OOM(aLength);
1.163 + }
1.164 + }
1.165 +
1.166 + /**
1.167 + * Append a substring of the contents of this string fragment to aString.
1.168 + * @param aString the string in which to append
1.169 + * @param aOffset where to start the substring in this text fragment
1.170 + * @param aLength the length of the substring
1.171 + * @return false if an out of memory condition is detected, true otherwise
1.172 + */
1.173 + bool AppendTo(nsAString& aString, int32_t aOffset, int32_t aLength,
1.174 + const mozilla::fallible_t&) const NS_WARN_UNUSED_RESULT
1.175 + {
1.176 + if (mState.mIs2b) {
1.177 + bool ok = aString.Append(m2b + aOffset, aLength, mozilla::fallible_t());
1.178 + if (!ok) {
1.179 + return false;
1.180 + }
1.181 +
1.182 + return true;
1.183 + } else {
1.184 + return AppendASCIItoUTF16(Substring(m1b + aOffset, aLength), aString,
1.185 + mozilla::fallible_t());
1.186 + }
1.187 + }
1.188 +
1.189 + /**
1.190 + * Make a copy of the fragments contents starting at offset for
1.191 + * count characters. The offset and count will be adjusted to
1.192 + * lie within the fragments data. The fragments data is converted if
1.193 + * necessary.
1.194 + */
1.195 + void CopyTo(char16_t *aDest, int32_t aOffset, int32_t aCount);
1.196 +
1.197 + /**
1.198 + * Return the character in the text-fragment at the given
1.199 + * index. This always returns a char16_t.
1.200 + */
1.201 + char16_t CharAt(int32_t aIndex) const
1.202 + {
1.203 + NS_ASSERTION(uint32_t(aIndex) < mState.mLength, "bad index");
1.204 + return mState.mIs2b ? m2b[aIndex] : static_cast<unsigned char>(m1b[aIndex]);
1.205 + }
1.206 +
1.207 + struct FragmentBits {
1.208 + // uint32_t to ensure that the values are unsigned, because we
1.209 + // want 0/1, not 0/-1!
1.210 + // Making these bool causes Windows to not actually pack them,
1.211 + // which causes crashes because we assume this structure is no more than
1.212 + // 32 bits!
1.213 + uint32_t mInHeap : 1;
1.214 + uint32_t mIs2b : 1;
1.215 + uint32_t mIsBidi : 1;
1.216 + uint32_t mLength : 29;
1.217 + };
1.218 +
1.219 + size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
1.220 +
1.221 +private:
1.222 + void ReleaseText();
1.223 +
1.224 + /**
1.225 + * Scan the contents of the fragment and turn on mState.mIsBidi if it
1.226 + * includes any Bidi characters.
1.227 + */
1.228 + void UpdateBidiFlag(const char16_t* aBuffer, uint32_t aLength);
1.229 +
1.230 + union {
1.231 + char16_t *m2b;
1.232 + const char *m1b; // This is const since it can point to shared data
1.233 + };
1.234 +
1.235 + union {
1.236 + uint32_t mAllBits;
1.237 + FragmentBits mState;
1.238 + };
1.239 +};
1.240 +
1.241 +#endif /* nsTextFragment_h___ */
1.242 +
